Exploring the Potential of β-Catenin O-GlcNAcylation by Using Fluorescence-Based Engineering and Imaging
Angélina Kasprowicz, Corentin Spriet, Christine Terryn, Vincent Rigolot, Stephan Hardivillé, Matthew G. Alteen, Tony Lefebvre, Christophe Biot
Abstract
Monitoring glycosylation changes within cells upon response to stimuli remains challenging because of the complexity of this large family of post-translational modifications (PTMs). We developed an original tool, enabling labeling and visualization of the cell cycle key-regulator β-catenin in its O-GlcNAcylated form, based on intramolecular Förster resonance energy transfer (FRET) technology in cells. We opted for a bioorthogonal chemical reporter strategy based on the dual-labeling of β-catenin with a green fluorescent protein (GFP) for protein sequence combined with a chemically-clicked imaging probe for PTM, resulting in a fast and easy to monitor qualitative FRET assay. We validated this technology by imaging the O-GlcNAcylation status of β-catenin in HeLa cells. The changes in O-GlcNAcylation of β-catenin were varied by perturbing global cellular O-GlcNAc levels with the inhibitors of O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Finally, we provided a flowchart demonstrating how this technology is transposable to any kind of glycosylation.